Elastic thread



April6,1937. T. HARRIS 2,076,273

ELASTIC THREAD Filed Sept. 30, 1935 INVEN TOR.

A TTORNEYS.

Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE ELASTIC THREADApplication September 30, 1935, Serial No. 42,743

16 Claims.

This invention relates to a covered elastic thread, and has for one ofits objects the provision of an elastic thread which will have acomplete covering thereabout, which covering will permit more freedom ofaction in expansion and contraction of the thread than the usual spunand twisted fibrous covering helically wrapped about' the core.

Another object of my invention is to limit the m elongation of the yarnby means of the covering.

Another object of the invention is the provision of an elastic threadwhich will not kink but rather lie flat when little or no tension isapplied thereto.

' Another object of the invention is to provide a 15 thread which willbe soft to the touch and extremely flexible and pliant.

Another object of the invention is to provide a core which will assistin retaining a non-twisted covering in position thereon.

Another object of the invention is the provision of a thread in whicheach of the plurality of coverings will be of untwisted fibers withadjacent layers of the covering wrapped in opposite directions about thecentral elastic core.

With these and other objects in view, the invention consists of certainnovel features of construction, as will be more fully described, andparticularly pointed out in the appended claims.

In the accompanying drawing:

Fig. l is an enlarged elevation showing the core and covering layers aspositioned on the core and wound in opposite directions;

Fig. 2 shows a yarn with a portion of one wrapping thereabout;

Fig. 3 is an enlarged view illustrating the yarn having a singlecovering layer as contracted and somewhat kinked by reason of the twistin the core; and

Fig. 4 is a diagrammatic View illustrating the 40 application of thesecond covering upon the elastic" core covered with one layer.

Fig. 5 is a perspective view of a twisted rubber core with a squarecross section.

Commercial elastic yarn at the present time 5 usually consists of arubber core about which there is helically wrapped a non-elastic twistedfibrous thread of material. This thread is wrapped about the core whenthe core is stretched and prevents contraction of the thread to its 50original naked rubber size, thus leaving the core constantly undertension. On the other hand, if this thread was not stretched to itslimit when covered, this covering would restrict the thread to a certainamount and prevent it from stretching 55 to the extent it wouldwithoutthe covering; thus.

the commercial yarn is limited in its contraction and extension, and inorder to provide a greater range of extension and contraction for acovered elastic thread I have used a covering of fibers which will berelatively untwisted and I wrap these on the elastic core by theirdelivery at substantially right angles to the travel of the core and ata speed which will cause the non-elastic fibers to be wrapped upon thecore with a very short pitch or at an angle approximating a right angleto the direction of travel of the core; and in order that a secondcovering may be assembled on the yarn I cause a twisting of thepreviously covered yarn in the opposite direction but with a smallernumber of turns per inch than that first used so that the twist placedin the core and its covering will be partially taken out at the time ofthe second covering of the yarn.

With reference to the drawing, the core may be a vulcanized rubberelastic thread although any suitable elastic core may be used which iscovered by non-elastic fibrous material II which is relatively untwistedand is usually positioned or placed upon the elastic core I!) when thesame is in stretched condition by reason of the elastic core beingoperated upon by an apparatus such as shown diagrammatically in Figure4. The rubber core is nipped by a pair of rolls I2 and also by a pair ofrolls M'which are traveling at a rate faster than the rolls l2 so as tostretch the rubber strand between the nips of the rolls I2 and i4 about400%. This stretch is maintained between the nip of the rolls l4 and thering and traveler of thepackaging means, by using a traveler ofsufiicient weight while at the same time a twist I is placed in therubber strand and at a point between the packaging means and the nip ofthe rolls l4 untwisted fibers approach at right angles to the travel ofthe core from a drafting mechanism to be delivered at a point Hi to bewrapped about the rubber core, thus placing a covering H upon the core,which covering by reason of its wrapping limits the extension of thecore.

It is found, however, that if tension is relaxed on the strand with thesingle covering thereon such as II that it will contract and kink up ortend to twist about itself giving somewhat the appearanceof the strandshown in Figure 3; in fact the contraction is such that the rubber isunder no tendency to further shorten the length which I may term astatic condition, and in order that the tendencyto kink may be reducedor eliminated I pass the strand consisting of the core l and itscovering ll again through a similar apparatus where the covered nippedby rolls l2 similar to that previously provided. However, in the secondpassage through a similar apparatus the spindle of the packaging meanswill be caused to travel in the opposite direction but at a speed toplace in the strand substantially half the twists or a sufiicient numberof twists to take out the kinks which would otherwise occur as abovementioned and shown in Figure 3; and in this passage I assemble a secondcovering l1 upon the core and covering I I in the opposite direction asshown more clearly in Figure 1, the second covering being delivered andassembled in a similar manner between the nip of the rolls l4 and thetraveler of the packaging means where the stretch is maintained and thetwist occurs, as before mentioned. i

In this manner I obtain two coverings l l and I1 upon a rubber core It,the rubber core being twisted in one direction to assemble the firstcovering thereon which thus is wrapped in the same direction as thetwist in the core, while the next covering is wrapped in the oppositedirection about the core and its cover at the same time removing some ofthe twists placed in the core in its first layer of covering, althoughleaving a suificient number of twists in this first applied core andcovering to maintain the same in assembled relation thereon, thedelivery in speed at the time of nipping being such that a very shortangle is provided which I find enables the coreto have a, large amountof elasticity before being bound by the covering thereon, and in thismanner the extension of the thread is greater and also the contractionof the thread is greater, thus providing more freedom of action and alonger range of extendibility and contractibility than that provided inthe covered thread having twisted yarns for forming the coveringthereon, while by reason of my double covering with these untwistedfibers I may take the kink out of the yarn enabling it to be betterhandled without tension.

The twisting of the core also assists in holding the non-twisted fibrouscovering on the core strand I0 is again especially upon contraction asthe surface provided by the twist tends to grip the innermost fibers ofthe covering and hold them fast upon the core. This is particularly truewhere a core of rectangular cross section such as shown at IS in Fig. 5,is used. The twisted corners I! of the square core are in somewhat of acorkscrew efi'ect and upon contraction bind the fibers of the coveringbetween them. The rectangular structure when twisted, becomessubstantially round for covering purposes. i

The foregoing description is directed solely towards the constructionillustrated, but I desire it to be understood that I reserve theprivilege of resorting to all the mechanical changes to which the deviceis susceptible, the invention being defined and limited only by theterms of the appended claims.

I claim:

- 1. An elastic single yarn comprising a twisted core of elasticmaterial covered by a strand wound thereabout in a helical path and inthe same direction as the twist of the core, said strand com prisingrelatively non-twisted fibers arranged sufficiently coherently by reasonof them being twisted about the core as to give them sufiicient strengthto limit the extension of the core material.

g. An elastic single yarn comprising a core of and I4 and cause astretch.

elastic material having relatively non-twisted fibers arranged in agenerally helical path about the core material and ,with a sufficientlylong pitch so that upon contraction the core material of the yarn mayreturn to substantially static condition under substantially no tensionand the covering substantially completely covers the core material inany degree of stretch.

3. An elastic yarncomprising a core of elastic material twistedsufiiciently to provide helical ridges along its surface and havingrelatively non-twisted fibers arranged in a generally helical path aboutthe core material and in a direction to cause the twisted core materialto assist in more securely holding the fibers assembled about the corematerial.

4. An elastic yarn comprising a core of elastic material twistedsufiiciently to provide helical ridges along its surface and havingrelatively non-twisted fibers arranged in a generally helical path aboutthe core material and in the same direction as the twist of the corewhereby the twisted core material assists in more securely holding thefibers assembled about the core material.

5. An elastic yarn comprising a core of substantially rectangular crosssection in condition twisted sufiiciently to provide helical ridgesalong its surface and relatively non-twisted fibers arranged in agenerally helical path about the core whereby the twisted core assistsin more securely holding the fibers assembled about the core.

6. An elastic single yarn comprising a twisted core of elastic materialhaving relatively nontwisted fibers arranged generally in a helical pathabout the core material in one direction and another layer of fibershelically disposed in the opposite direction about the first layer offibers, the twist in the core and the disposition of the fibers in theouter covering being substantially equal and opposite.

7. An elastic single yarn comprising a twisted core of elastic materialhaving relatively nontwisted fibers arranged generally in a helical pathabout the core material in one direction and another layer of relativelynon-twisted fibers helically disposed in the opposite direction aboutthe first layer of fibers, the twist in the core and the disposition ofthe fibers in the outer covering being substantially equal and opposite.

8. An elastic yarn comprising a twisted core of elastic material havingrelatively non-twisted fibers arranged in a generally helical path aboutthe core material in the same direction as the twist of the core andanother layer of fibers helically disposed in the opposite directionabout the first layer of fibers, with the pitch of said helical pathsufiiciently long to permit contraction and prevent the core from beingheld under tension when released.

9. An elastic yarn comprising a twisted core of elastic material havingrelatively non-twisted fibers arranged in agenerally helical path aboutthe core material and in the same direction as the twist of the core andanother layer of fibers helically disposed in the opposite directionabout the first layer of fibers.

10. An elastic yarn comprising a twisted core of elastic material havingrelatively non-twisted fibers arranged in a generally helical path aboutthe core material in one direction and in the same direction as thetwist of the core and another layer of non-twisted fibers helicallydisposed in the opposite direction about the first layer of fibers, thetwist in thecore and the disposition of the fibers in the outer coveringbeing substantially equal and opposite.

11. The method of forming elastic yarn which 6 consists in twisting andadvancing an elastic strand under tension and wrapping thereaboutrelatively non-twisted fibers in a helical path by reason of saidtwisting with the pitch of said helical path sufiiciently long to permitcontraction and prevent the core from being held under tension whenreleased.

12. The method of forming a covered elastic thread which consists infeeding an elastic core in stretched condition, twisting it about itspath of travel and delivering relatively nontwisted fibers atsubstantially right angles to the path of travel of said core to wrapthe core in a helical path said wrapping of the fibers twisting themsufficiently to give them strength to 2 limit the extension of the core.

13. The method of forming a covered elastic thread; which consists infeeding an elastic core in stretched condition, twisting it about itspath of travel by revolving only one of its ends and deliveringrelatively non-twisted fibers at substantially right angles to the pathof travel of said core to wrap the core in a helical path, said wrappingof the fibers twisting them sufficiently to give them strength to limitthe ex- 30 tension of the core.

14. The method of forming a covered elastic yarn, which consists infeeding and stretching an elastic core, then maintaining said core instretched condition and twisting it subse- 35 quently to saidstretching, and drafting relative- 1y non-twisted fibers and deliveringthem to said core without twisting the fibers to wrap the core in ahelical path, said wrapping of the fibers twisting them sufiiciently togive them strength to limit the extension of the core and the pitch ofsaid wrapping being sufiiciently long so as to permit contraction tosuch an extent that the elastic core is under substantially no tension.

15. The method of forming a covered elastic yarn, which consists infeeding and stretching an elastic core, then maintaining said core instretched condition and twisting it subsequently to said stretching byrevolving only its delivery end, and drafting relatively non-twistedfibers and delivering them to said core without twist to wrap the corein a helical path, said wrapping 'of the fibers twisting themsufiiciently to give them strength to limit the extension of the coreand the pitch of said wrapping being sufliciently long so as to permitcontraction to such an extent that the elastic core is undersubstantially no tension.

16. The method of forming a covered elastic, yarn, which consists intwisting and advancing an elastic core and delivering relativelynon-twisted fibers to said core to wrap about the core in a helical pathand subsequently twisting the covered core in the opposite direction bya lesser number of revolutions and advancing the same whilesimultaneously delivering nontwisted fibers to said covered core" towrap about the same and form a second layer of covering on the core.

THOMAS HARRIS.

